ABSTRACT
Voice communication is in the midst of an evolution toward network convergence. Over the past several
decades, the coalescence of voice and data through the circuit-based, voice-centric public switched
telephone network (PSTN) has been limited. Interconnected networks exist today, each maintaining its
own set of devices, services, service levels, skill sets, and security standards. These networks anticipate the
inevitable and ongoing convergence onto packet-or cell-based, data-centric networks primarily built for
the Internet. Recent deregulation changes and cost savings, as well as the potential for new media
applications and services, are now driving a progressive move toward voice over some combination of
ATM, IP, and MPLS. This new-generation network aims to include novel types of telephony services that
utilize packet-switching technology to receive transmission efficiencies while also allowing voice to be
packaged in more standard data applications. New security models that include encryption and security
services are necessary in telecommunication devices and networks.
